a. Field of Invention
This invention pertains to an electric-motor drive arrangement for operating windows, sliding roofs and the like, particularly in motor vehicles, and more particularly to a commutator motor with a switch sensitive to short-circuit currents, said switch being integrally made with the commutator brushes.
An electric motor drive arrangement is disclosed in German Pat. No. 31 51 307. In this known arrangement, an operating switch is held in the closed position by the ac voltage induced when the motor is running. The induced ac voltage is sensed by a separate conductor coil which is arranged in the external connecting line in series with the commutator motor. The induced ac voltage is decoupled from the ground dc voltage by a capacitor, and is then amplified and rectified, and used for holding the operating switch in the closed position.
b. Objectives and Summary of the Invention
It is an objective of the present invention to reduce the amount of structure and the production time, as well as the overall size of a commutator motor used for operating devices such as windows, sliding roofs and the like in motor vehicles.
A further objective is to provide a motor which is turned off relatively rapidly under short circuit conditions, for instance, when the driven device reaches an end position.
Through the structure according to the invention, the expense for a separate inductance and its installation and its electrical connection can be dispensed with since it is incorporated or mounted on the radio interference suppression chokes already provided. Such chokes, for instance as described in German Pat. No. 28 14 009 or DE-AS No. 28 13 956 are used for radio interference suppression of the commutator motor in the brush holders are concurrrently used for determining the induced ac voltage.
In a particularly simple manner, the operating switch is coupled electrically to a radio interference suppression choke by a sensing winding wound around the radio interference suppression choke.